Many different electrical tilt and vibration switches are presently available and known to those having ordinary skill in the art. Typically, tilt switches are used to switch electrical circuits ON and OFF depending on an angle of inclination of the tilt switch. These types of tilt switches typically contain a free moving conductive element located within the switch, where the conductive element contacts two terminals when the conductive element is moved into a specific position, thereby completing a conductive path. An example of this type of tilt switch is a mercury switch. Unfortunately, it has been proven that use of Mercury may lead to environmental concerns, thereby leading to regulation on Mercury use and increased cost of Mercury containing products, including switches.
To replace Mercury switches, newer switches use a conductive element capable of moving freely within a confined area. A popularly used conductive element is a single metallic ball. Tilt switches having a single metallic ball are capable of turning ON and OFF in accordance with a tilt angle of the tilt switch. Certain tilt switches also contain a ridge, a bump, or a recess, that prevents movement of the single metallic ball from a closed position (ON) to an open position (OFF) unless the tilt angle of the tilt switch is in excess of a predetermined angle.
An example of a tilt switch requiring exceeding of a tilt angle of the tilt switch is provided by U.S. Pat. No. 5,136,157, issued to Blair on Aug. 4, 1992 (hereafter, the '157 patent). The '157 patent discloses a tilt switch having a metallic ball and two conductive end pieces separated by a non-conductive element. The two conductive end pieces each have two support edges. A first support edge of the first conductive end piece and a first support edge of the second conductive end piece support the metallic ball there-between, thereby maintaining electrical communication between the first conductive end piece and the second conductive end piece. Maintaining electrical communication between the first conductive end piece and the second conductive end piece keeps the tilt switch in a closed position (ON). To change the tilt switch into an open position (OFF), the metallic ball is required to be moved so that the metallic ball is not connected to both the first conductive end piece and the second conductive end piece. Therefore, changing the tilt switch into an open position (OFF) requires tilting of the '157 patent tilt switch past a predefined tilt angle, thereby removing the metallic ball from location between the first and second conductive end piece. Unfortunately, tilt switches generally are not useful in detecting minimal motion, regardless of the tilt angle.
Referring to vibration switches, typically a vibration switch will have a multitude of components that are used to maintain at least one conductive element in a position providing electrical communication between a first conductive end piece and a second conductive end piece. An example of a vibration switch having a multitude of components is provided by U.S. Pat. No. 6,706,979 issued to Chou on Mar. 16, 2004 (hereafter, the '979 patent). In one embodiment of Chou, the '979 patent discloses a vibration switch having a conductive housing containing an upper wall, a lower wall, and a first electric contact body. The upper wall and the lower wall of the conductive housing define an accommodation chamber. The conductive housing contains an electrical terminal connected to the first electric contact body for allowing electricity to traverse the housing. A second electric contact body, which is separate from the conductive housing, is situated between the upper wall and lower wall of the conductive housing (i.e., within the accommodation chamber). The second electric contact body is maintained in position within the accommodation chamber by an insulating plug having a through hole for allowing an electrical terminal to fit therein.
Both the first electrical contact body and the second electrical contact body are concave in shape to allow a first and a second conductive ball to move thereon. Specifically, the conductive balls are adjacently located within the accommodation chamber with the first and second electric contact bodies. Due to gravity, the '979 patent first embodiment vibration switch is typically in a closed position (ON), where electrical communication is maintained from the first electrical contact body, to the first and second conductive balls, to the second electrical contact body, and finally to the electrical terminal.
In an alternative embodiment, the '979 patent discloses a vibration switch that differs from the vibration switch of the above embodiment by having the first electrical contact body separate from the conductive housing, yet still entirely located between the upper and lower walls of the housing, and an additional insulating plug, through hole and electrical terminal. Unfortunately, the many portions of the '979 patent vibration switch result in more time required for construction and assembly, in addition to higher cost. Furthermore, the '979 patent presents a vibration switch that cannot be mounted to the surface of a printed circuit board (PCB).
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.